[libclc] [libclc] Restore always_inline for SPIR-V targets (PR #202891)

[Matt Arsenault via cfe-commits]

arsenm wrote:

> `-disable-llvm-passes` should be better than `-O0`. SPIRV is generic target and doesn't have TTI interface, 

SPIRV is a distinct target that can implement TTI 



https://github.com/llvm/llvm-project/pull/202891